security. >> reporter: the port authority and raytheon say they are being corrected and increased patrols and working to make sure someone more serious than a lost jet skier never walks across runways at the jfk terminal again. for "nightline," i'm jim avila in new york. >> our thanks to jim. just ahead, it was the assignment that saved my life or so i thought until a second, third and fourth opinion and tonight, i'll challenge one famous doctor to defend his methods and diagnosis next. [ male announcer ] this is karen and jeremiah. they don't know it yet, but they're gonna fall in love, get married, have a couple of kids, [ children laughing ] move to the country, and live a long, happy life together where they almost never fight about money. [ dog barks ] because right after they get married, they'll find some retirement people who are paid on salary, not commission. they'll get straightforward guidance and be able to focus on other things, like each other, which isn't rocket science. it's just common sense.